i'm hopeless at percentages

i haven't done maths for years, and now i'm face with it again at uni.

1) The shorelines of the earth (including lakes and the arctic and antarctic regions) total about 440 000km in length over ten times the earth's perimeter. If everyone of the world population (3.8 x 10*9 in 1974) decided to possess a portion of this shoreline, how much would he have on the average?